code: def copy(self):
      other = RunningStat()
      other._n = self._n
      other._M = np.copy(self._M)
      other._S = np.copy(self._S)
      return other
  
imports: import numpy
label_desc: Use image node_id 2 for calling the RunningStat obj's underlying member method code with example usage: obj.copy() and returns: other